#pragma once
/**
 * \file
 * Functions and types for CRC checks.
 *
 * Generated on Thu Jan  1 10:43:11 2026
 * by pycrc v0.11.0, https://pycrc.org
 * using the configuration:
 *  - Width         = 32
 *  - Poly          = 0x04c11db7
 *  - XorIn         = 0xffffffff
 *  - ReflectIn     = True
 *  - XorOut        = 0xffffffff
 *  - ReflectOut    = True
 *  - Algorithm     = bit-by-bit-fast
 *
 * This file defines the functions crc_init(), crc_update() and crc_finalize().
 *
 * The crc_init() function returns the initial \c crc value and must be called
 * before the first call to crc_update().
 * Similarly, the crc_finalize() function must be called after the last call
 * to crc_update(), before the \c crc is being used.
 * is being used.
 *
 * The crc_update() function can be called any number of times (including zero
 * times) in between the crc_init() and crc_finalize() calls.
 *
 * This pseudo-code shows an example usage of the API:
 * \code{.c}
 * crc_t crc;
 * unsigned char data[MAX_DATA_LEN];
 * size_t data_len;
 *
 * crc = crc_init();
 * while ((data_len = read_data(data, MAX_DATA_LEN)) > 0) {
 *     crc = crc_update(crc, data, data_len);
 * }
 * crc = crc_finalize(crc);
 * \endcode
 */
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>


/**
 * The type of the CRC values.
 *
 * This type must be big enough to contain at least 32 bits.
 */
typedef uint_fast32_t crc_t;


/**
 * Reflect all bits of a \a data word of \a data_len bytes.
 *
 * \param[in] data     The data word to be reflected.
 * \param[in] data_len The width of \a data expressed in number of bits.
 * \return             The reflected data.
 */
crc_t crc_reflect(crc_t data, size_t data_len)
{
    unsigned int i;
    crc_t ret;

    ret = data & 0x01;
    for (i = 1; i < data_len; i++) {
        data >>= 1;
        ret = (ret << 1) | (data & 0x01);
    }
    return ret;
}


/**
 * Calculate the initial crc value.
 *
 * \return     The initial crc value.
 */
static inline crc_t crc_init(void)
{
    return 0xffffffff;
}


/**
 * Update the crc value with new data.
 *
 * \param[in] crc      The current crc value.
 * \param[in] data     Pointer to a buffer of \a data_len bytes.
 * \param[in] data_len Number of bytes in the \a data buffer.
 * \return             The updated crc value.
 */
crc_t crc_update(crc_t crc, const void *data, size_t data_len)
{
    const unsigned char *d = (const unsigned char *)data;
    unsigned int i;
    crc_t bit;
    unsigned char c;

    while (data_len--) {
        c = *d++;
        for (i = 0x01; i & 0xff; i <<= 1) {
            bit = (crc & 0x80000000) ^ ((c & i) ? 0x80000000 : 0);
            crc <<= 1;
            if (bit) {
                crc ^= 0x04c11db7;
            }
        }
        crc &= 0xffffffff;
    }
    return crc & 0xffffffff;
}


/**
 * Calculate the final crc value.
 *
 * \param[in] crc  The current crc value.
 * \return     The final crc value.
 */
static inline crc_t crc_finalize(crc_t crc)
{
    return crc_reflect(crc, 32) ^ 0xffffffff;
}